Comparator device



J. D. COAKLEY COMPARATOR DEVICE May 1, 1951 2 Sheets-Sheet 1 Filed Oct. 22, 1948 2 5 MHW M OOOOO% way/V0. CUAVfZ/f/ INVENTOR.

ATTORNEY J. D. COAKLEY COMPARATOR DEVICE May 1, 1951 2 Sheets-$heet 2 Filed Oct. 22, 1948 ATTOENEY Patented May 1, 1951 UNITED STATES PATENT OFFICE COMPARATOR DEVICE John D. Coakley, Cos Cob, Conn.

Application October 22, 1948, Serial No. 55,870

7 Claims.

The present invention relates to devices adapted to checking articles with a view to assuring uniformity. More particularly, it relates to automatic scanning devices for labels to ensure the correct labeling of articles, such as drugs, where the misla-beling or false labeling constitutes a serious danger.

In the drug manufacturing industry many of the operations are conducted by automatic me- .chanical devices. Among these operations is the labeling of bottles or other containers and it is of extreme importance that each bottle or other type of container should bear a label correctly denoting its contents. It happens, however, that, either through negligence or because of other failure, a container may be mislabeled. It sometimes occurs where labeling machines are used that the wrong batch of labels is fed to the labeling machine. It more frequently happens when through inadvertence one or more wrong labels are mixed in a batch of correct labels. In this case the error is extremely difficult to detect.

It is an object of the present invention to provide a device to scan labels as they are fed from a stack to a standard labeling machine, and to accept and pass on all correct labels but to reject incorrect labels so that they will not be placed on the containers.

Briefly described, the device includes a standard plate bearing a code indication corresponding to a similar code borne by a tab aflixed to the label that is to be applied to the containers. The standard plate may be stamped out or it may be made up of removable lugs so that by readjusting the lugs the code indications may be changed for other drugs. The code is a binary numerical codethat is, a number written to the base two and this code is printed on the label at the same time that the label is printed. It is, however, not printed upon the label proper but upon a tab or extension of the label which is later cut off or otherwise removed from the label after it passes the automatic verifying device of the invention and before it is gummed on to the container. While the code is based on a numerical system, it is actually printed as a series of square blocks and spaces and for reasons of convenience these blocks and spaces are printed in two rows, one above the other. It is, however, within the contemplation of the invention that there might be a single row or more thantwo rows, and the blocks or squares may be printed either in black or colored ink on a light background. I During the operation of the machine the label tab bearing the code indication is passed before appropriately positioned photoelectric cells and suitable circuits hereinafter described co-operating in conjunction with the standard plate to energize the system so long as the code on the tabs of the labels passing before the photoelectric cells conforms to the code indications on the standard plate. If, however, a wrong label bearing a different code indication comes before the photoelectric cells, there is immediate stoppage of the whole system which cannot begin to work again until the defective label is removed from the stack. When, however, the labels passing before the photoelectric cells are accepted by the machine, they are passed on to a cutting device which removes the tab bearing the code indication and they are then fed to the labeling machine which gums the labels to the bottles or other containers. Accordingly, the label as attached to the container shows no evidence of the code indication tab by which it was selected.

It has been previously suggested to print a code directly on the label or to perforate the label with code indications and then to scan the labels either visually or mechanically. Such systems are objectionable partly because of the error inherent in the human equation and partly because the label is changed in appearance and often marred. A well known label, for instance, is part of the good will of the concern using it as it frequently bears the trademark of that concern, and if it is printed over or perforated, the appearance thereof is changed so that it is not as easily recognized.

The device of the present invention is intended to be used with standard labeling machines. Such machines feed labels from a stack and irrespective of the label size the forward edge of the labels remains in the same location in the labeling machine.

According to the present invention it is proposed to locate the tab bearing the code indication preferably along the forward edge either at the center thereof or at either side. How-- ever, if the length of the tab bearing the code indication is kept short and the code is arranged in two rows, the cutting off and the handling of the tab will be facilitated.

The invention will be more clearly understood from the drawings in which Fig. I is a diagrammatic representation of an electric circuit operating the comparator mechanism of the device of the invention; Fig. II represents diagrammatically a scanning head of the comparator mechanism of the invention viewed from one side; Fig. III represents diagrammatically the scanning head of Fig. II viewed from the end; Fig. IV illustrates one form of standard plate, included in the circuit of Fig. I; Fig. V is a diagrammatic representation of a stepping relay also included in the circuit of Fig. I; and VI, VII, VIII and IX illustrate positions of the scanning head as it rotates during operation.

The comparator mechanism comprises an electrical system shown diagrammatically in Fig. I, the code on the tab of the label being indicated at I, a pair of photoelectric cells indicated at 2, the code standard or code master indicated at 3, and an amplifier system indicated at t as tapped off from the center of the coil 2*. Athree position relay includes a contact arm and -a circuit con trolled by the switch a: and including the conductor 6, the coil magnet I, the roller switch 8 and the co-operating contacts 9 9 9 and 5. As the label tab is "advanced in front of the photoelectric cells, which in the drawing (Fig. I) are shown as two in number and the code indications as in two rows, in the position shown there will be a less current through the circuit controlled by "the photoelectric cell over the black square than in the circuit controlled by the photoelectric cell which is over the white space. Accordingly, the contact arm of the three way "relay will be moved so as to effect connection with the contact pointe the contact arm of roller switch 8 governed by the code master 3 moving synchronously to contact the contact point 9 and thus to close the circuit including conductor I5 and coil magnet I.

'So long as the code on the label tab I is in conformity with the contour of the code standard or code master 3, there will be a variation of current through the photoelectric cells governed by the black squares and white spaces on the tab of the label, and the three position relay will move back and forth between the contacts 9 and 9 and a neutral point midway between these contacts. Similarly, the roller switch 8 will move between the contac'tpoints 9F and 9 If, how- 'ever, a wrongly coded label should be advanced before the photoelectric cells, the three position relay would at some point during the passage of the label be moved so that the arm would contact the wrong contact point as between contacts 9 and 9 In such case, however, the roller switch 8 moving over the contour of the code standard or code master 3 would be in such position that the circuit would be broken since the contact arms would be out of the proper contact that the code standard required as between contact points 9 and 9 while the arm of the roller switch would be in the proper contactas between contact points 9 and 9 A stepping relay, of which magnet coil I forms apart, would in the meanwhile move a contact arm 52 from one contact point I3 to another, step by step, until the three point relay arm and roller switch arm 3 are out of agreement. In this case one or more steps of the stepping relay are missed so that the contact arm I2 of the stepping relay does not reach the final contact point I in before the scanning period is ended. At the end of the scanning period the switch I4 is opened by mechanical means such as, for instance, a cam (not shown) which may be on the main shaft of the labelling machine. With the contact arm I2 in contact with a contact point short of contact point I3 and the switch I t open, it will be obvious that the circuit including magnet coil I5 will be broken and the magnet coil I5 will be deenergized. In that case the spring It will pull down the valve I! to shut off the vacuum line It. When this occurs, the pick up head of the labelling machine will fail to operate and the wrong label will not be picked up by the labelling machine. At the same time the contact arm I2 is reset at the first contact point I3 by action of the coil 23. When the wrong label is removed and a correct label appears at the top of the stack, the operation of the device is resumed.

It will be seen that the operation is as follows:

A lamp IE) and lens II project light upon the tab I of the label and the light is reflected back to actuate the photoelectric cells 2 ii the code conforms to the code master 3. The light reflected from the white part of the tab surface will, of course, be greater than that from black or colored squares of the tab.

The two photoelectric cells 2 and the lamp I0 and lens II move over the tab of the label at the top of the stack. In the position shown in Fig-I, less current flows through the cell which is over the black square than through the cell that is over the light background of the tab. Consequently, the current in coil 2 is less than the current in coil 2. The difference in current is amplified in the amplifier system t and applied to the polarized three position relay 5. As a result the contact arm of the relay swings into contact with contact point 9 The label code master 3, which is a properly shaped metal 'plate or cam shown in detail in Fig. IV, moving synchronously with the label tab I, has at the same time moved the contact arm of the roller switch 8.

In normal conditions, i. e., where a label tab I conforming to the standard or code master 3 is under the scanning head, the contact 'arm 5 will be in contact with contact point 9* at the same time that the arm of the roller switch 8 is in contact with contact point 9 and thus the magnet l is energized through conductor 6, both of which are in the circuit now closed by arms 5 and 8 and contact points 9 and 9. Again, as the photoelectric cells 2 move over the tab I, the arms 5 and 8 will contact the contactpoints 9 and 9", which position also closes the circuit and energized magnet I. As a consequence the coil I5 is energized and this draws up the element I'I,

thereby opening the vacuum line I8 which operates the pick up head of the labelling machine. A tab bearing a wrong code, not conforming to code master 3, will, however, deenergize the coil 7 and thecoil I5, whereupon the spring I6 will pull the element I'I down to close the vacuum line I3. When this happens, the pick up head cannot pick up the incorrect label. The operation of the device will not resume until the "improper label is removed. The device fails but it fails safely. Thus, failure of the mechanismto operate results in rejection of the label as defective and not in accord with'the code master or standard 3.

The operation of the stepping relay'shown in Fig. V is as follows 2 The code master 3 moves in synchronism with the label I of Fig I and as the contact arm ii of the three point relay is swung into contact with contact point 9 the code master 3 has at the same time swung the contact 'arm 8 into contact with contact point 9, thus closing the circuit including the magnet coil I, thus energizing the stepping relay thatincludes'the contact arm I2 and the contact points I3. when'the-photoelec tric cells have passed the first black square of the code on the label I, both cells are over the white background between the black squares or places of the code, and the arm 3 of the roller switch co-operating with the code master 3 returns to center, a neutral point out of contact with either the contact point 9 or contact point 9 and the magnet coil 1 is consequently deenergized. The contact arm l2 of the stepping relay has in the meanwhile moved from the first contact point to the second. As the black dots 01' squares successively come before the photoelectric cells, the contact arm [2 of the stepping relay advances step by step along the contact points I3. Thus, unless the printed code and the code master are in agreement at each place, the circuit through the magnet coil will not be closed for each place of the code tab and the contact arm I2 will miss one or more steps and will not reach the final contact point 13 by the end of the scanning period.

At the end of the scanning period for each tab, the switch id is opened by a cam on the main shaft of the labelling machine. If by the end of the scanning period the contact arm :2 has not stepped all the way across the contact points [3, then the circuit through the magnet I5 is deenergized and a spring l5 pulls the valve ii to close the vacuum line [8 leading to the pick up head of the labelling machine. Without vacuum it is obvious that the label pickup head will not pick up the label presented to it.

The stepping relay is shown diagrammatically in Fig. V. It will be seen that the contact arm {2 of the stepping relay rotates on the shaft 19 moving, as hereinbefore described, around the contact points 13 step by step as the coil 1 is energized as above described. The gear wheel .29 on the shaft i9 is engaged and moved step by step by a pawl 2| and checked by dog 22. As the coil 7 is energized, the pawl 2| moves the toothed wheel 2i] and accordingly the shaft [9 so as to move the contact arm [2 from one contact point [3 to another and simultaneously the dog 22 engage the toothed wheel and checks it from moving backward. When the stepping relay contact arm [2 has reached the final contact point i3, it is returned to its original position by the closing of the cam switch 24 which energizes the coil 23 and thus releases the dog 22 permitting the toothed wheel 28 to rotate backwards to its original position by reason of the force exerted by spring 23 around the shaft 19.

The pawl 2! is moved by the pull of the magnet coil 7 but this motion is limited by an opening 21 in the base 28 through which the pawl extends. A spring 29 pulls against the force exerted by the coil 1 so that when coil 1 is deenergized the pawl 2i is pulled back to engage a following tooth which it will move in response to the next pull of the reenergized coil 7 and thus move the contact arm l2 tothe next contact of the points IS.

The mechanism of the comparator is shown in Figs. II and III and its operation is illustrated in Figs. VI, VII, VIII and IX.

This mechanism is positioned behind the label stack of the labeling machine and rotates on a vertical shaft 38 which is moved by a self-contained gear box 3!. The power may be taken from a line shaft of the labelling machine, not shown, the motion being converted into cyclic motion in known manner, or it may be otherwise powered. An arm 32 is keyed to shaft and. a scanning head 33 is carried thereon. The shaft 30 carries a commutator 34 and brush block 35. The brush block 35 floats on an extension of shaft 39 and does not turn with it.

As the shaft 30 revolves, the arm 32 revolves carrying the scanning head in rotation about it. The scanning head carries the photoelectric cell or cells 2 which are so disposed as to read the code indications in sequence in response, of course, to the light projected to the code tab l by the lamp It through the lens I l and reflected from the tab l to the photoelectric cells 2.

As stated, the scanning head rotates on the shaft 30 and, as shown in Figs. VI, VII, VIII and IX, describes a circle. In Fig. VI the scanning head 33 in its rotation on arm 32 approaches the code tab I. In Fig. VII it is over the code tab 1 in reading position. As the scanning head 33 swings into reading position it decelerates to a uniform motion accommodating the operation of the relay contact arms 5, 8 and !2. After the scanning period is completed, the scanning head 33 accelerates to maximum speed and by the time it has reached the position shown in Fig. VIII the cutting mechanism which may be of any well known type has cut the tab 5 from the label. In the position shown in Fig. IX the label is ready to be picked up by the pick up head of the labeling machine and affixed to the container, while the scanning head 33 is ready to start again to verify the next label on the label stack.

Having thus described my invention, what I claim is:

1. In combination with a labeling machine including a stack of labels, each label bearing code indicia and a vacuum operated device to pick up a label from said stack, a scanning device adapted and arranged to rotate in an orbit passing over said code indicia of said labels, said scanning device including a light source and optical system projecting the light from said light source on to said code indicia, and photoelectric cells in a circuit energized by the reflected light from said code indicia; a three way relay and circuit including the same and also including a code master element conforming to said code indicia, and a magnet coil adapted and arranged to be energized and deenergized by said three way relay and said code master element; a stepping relay operable by said magnet and a second magnet included in said stepping relay circuit adapted and arranged to open and shut a vacuum system connected with the pick-up head of said labeling machine whereby when said code indicia on said label is not in agreement with said code master element, said vacuum system will close.

" 2. In combination with a labeling machine including a vacuum pick-up system, a scanning device including a light source and photoelectric cells in a rotating scanning head adapted and arranged to pass over a stack of labels bearing code indicia in a labeling machine and to project light on the top label of said stack, said photoelectric cells being activated by reflected light from said top label; a three way relay, a code master element, and magnetic means responsive to said photoelectric cells for operating said relay in agreement with said code master element; other magnetic means adapted to be energizd and de-energized by said three way relay and included in the circuit of a stepping relay whereby when said other magnetic means is energized a vacuum system is opened and said labeling machine will pick up the top label from said stack and when said magnetic means is de-energized said vacuum system is closed and said labeling machine cannot pick up said top-label.

3. In combination with a labeling machine including a stack of label bearing code indicia thereon and a suction device to pick up one label at a time from said stack,-a scanning device including a rotating scanning head adapted and --arranged to pass over said stack of labels, said scanning head including means for projecting nets, a code master element in agreement with said code indicia and magnetic means for opening and closing the suction lines or said pickup device of said labeling machine, whereby when said code indicia on any label under said scanning head is out of agreement with said code master element said suction lines will be closed and said pick-up device will fail to operate.

4. In combination with a lebeling inachine'ineluding a stack of labels caring code indicia and a suction device adapted to pick up one label at a time from said stack, a circuit controlled by-a code master element in agreement with said code indicia and including ph-otoelectricmeans adapted to be energized by light reflected from said code indicia and magnetic means adapted to render said suction device inoperable when said code master element and said code indicia are not'in agreement.

5. In a labeling machine adapted to hold a stack of labels and provided with a suction device to pick up one label at a tim from said stack, a rotating scanning head adapted and ar-- ranged to control said suction device, said scanning head including a code master element in agreement with a code printed on said-labels, an electrical circuit including said code master element and a source of light adapted to project light upon the code indicia on 'said labels, photoelectric cells adapted to receive reflected light from said code indicia and thereby to activate said circuit and a stepping relay also in said circuit adapted to open and close the vacuum system of said suction device whereby so long as said code indioia on said labels of said stack are in agreement with said code master element,

c said suction device will operate to pick up labels from said stack.

5. 'In combination with a labeling machine including a suction device adapted to pick up labels bearing code indicia from a stack placed in said machine, a photoelectric system adapted to opcrate a three way relay in response to .light irefle'cted from said code indicia throughsaid photoelectric system; a code master element in agreem'ent with said code indicia co-operating with said three way relay-to closeand maintainclosed a circuit when-saidcode master element-and said code indicia are in agreement and to break said circuit when they are out of agreement; a stepping'relay in said circuit-and "adapted to operate when-saidcircuit is closed; and magnetic means controlled by said stepping relay to keep open the suction lines of said suction device when said code master circuit is closed and to permit closure of said suction'lines when said code master circuit is broken. a

7. Ina labeling machinaa pick-up device suctionally operated and a scanningdevice controllingthe suction line ofsaidpick-updevice, said scanning device consisting of a circuit including a photoelectric system to'energize the same, a three way relay, a code master element and a stepping relay adapted to energize a'magn'etcontrolling a valve to open and close-said suction system; said code master element being-in agreement with predetermined code indicia affixed to labels worked on'by said pick-up device, whereby when light is reflected'to said photoelectric'system from said predetermined code indioia said circuit operates to maintain'said suctionline open but when code indicia varying from saidpredetermined code are presented to said-photoelectric system said circuit is deenergized and said valve closes saidsuction line.

JOHN D. COAKLEY.

REFERENCES CITED The following references are of record'in'the file of this "patent:

UNITED STATES PATENTS Number Name Date 1,957,812 Stein May 8, 1934 2,262,573 Bender Nov. 11, 1941 2,464,561 Dickinson Mar. 15,1949 

